High-Current Wide-Wound Chip Inductor Selection Guide

Designers often struggle to find a high-current wide-wound chip inductor that meets both saturation-current and DCR limits while still fitting into compact footprints. This guide provides a clear selection path, exact part-to-part comparisons, and practical design tips so you can pick the right SMD component in minutes—not days.

1. Why Wide-Wound Chip Inductors Matter

Wide-wound construction increases conductor cross-section, lowering DC resistance (DCR) and pushing saturation current (I_SAT) above 10 A in footprints as small as 7 mm × 7 mm. This makes them ideal for high-current buck converters, PoE PSE controllers, and automotive LED drivers where every milliohm counts.

2. Key Specifications in Plain English

Spec	What It Tells You	Typical Range	Watch-Out
I_SAT	Current where inductance drops 30 %	5 A – 80 A	Check at 100 °C, not 25 °C
DCR	Copper losses → heat	0.4 mΩ – 15 mΩ	Multiply by I_RMS²
SRF	Freq where part turns capacitive	1 MHz – 15 MHz	Keep switching freq ≤ SRF/10
Footprint	L×W in mm	4×4 – 12×12	Height often 4 mm – 8 mm

3. Datasheet-Level Comparison Table (Popular 7 mm × 7 mm Parts)

Part Number	L (µH)	I_SAT (A)	I_RMS (A)	DCR (mΩ)	SRF (MHz)	Height (mm)
WWC-4770-R47	0.47	45	35	0.52	13	5.0
WWC-4770-1R0	1.0	32	25	0.85	9	5.0
WWC-4770-2R2	2.2	22	18	1.40	6.5	5.0
WWC-4770-4R7	4.7	14	12	2.80	4.8	5.0

Values measured at 25 °C unless noted. Use derating curves for 100 °C ambient.

4. The Hidden Problem: AC Ripple Heating

Many engineers focus on I_SAT but overlook high-current wide-wound chip inductor AC ripple heating. A 5 A ripple at 500 kHz can add 10 °C–15 °C to core temperature, silently pushing the part past its thermal limit.

5. Step-by-Step Solution & Layout Tips

Measure real ripple: Add 0.1 Ω sense resistor in series; scope I_RIPPLE.
Example: 4 A pk-pk at 500 kHz → I_RMS ≈ 1.15 A.
Calculate core loss P_CORE:
P_CORE ≈ k × f^1.3 × B^2.2 × V_e.
For the WWC-4770-1R0, k ≈ 3.3×10^-6, giving 0.35 W at 500 kHz, 100 mT.
Check temperature rise:
ΔT = P_TOTAL × R_θJA. With 40 °C/W thermal resistance, 0.6 W total → 24 °C rise.
Layout fixes:

Use 2-oz copper pours on top and inner layers directly under the inductor.
Place 4–6 thermal vias (0.3 mm dia) in the pad to spread heat.
Keep 3 mm clearance to noisy SW node to reduce EMI.

6. 30-Second Selection Checklist

✅ I_PEAK ≤ 0.7 × I_SAT @ 100 °C
✅ DCR × I_RMS² ≤ 0.5 W
✅ Switching freq ≤ SRF/10
✅ Height < 6 mm for PCIe card applications

Follow these steps and the high-current wide-wound chip inductor you choose will run cool, quiet, and reliable—even at 50 A load.

High-Current Wide-Wound Chip Inductor Selection Guide